A recap of the July 4 excitement as NASA’s Juno spacecraft entered orbit around Jupiter. After an almost five-year journey to the solar system’s largest planet, Juno successfully entered Jupiter’s orbit during a 35-minute engine burn. Confirmation that the burn had completed was received on Earth at 8:53 pm. PDT (11:53 p.m. EDT) Monday, July 4. For more about Juno, visit http://nasa.gov/juno and http://missionjuno.swri.edu.

NASA’s Juno spacecraft captured a unique time-lapse movie of the Galilean satellites in motion about Jupiter. The movie begins on June 12th with Juno 10 million miles from Jupiter, and ends on June 29th, 3 million miles distant. The innermost moon is volcanic Io; next in line is the ice-crusted ocean world Europa, followed by massive Ganymede, and finally, heavily cratered Callisto. Galileo observed these moons to change position with respect to Jupiter over the course of a few nights. From this observation he realized that the moons were orbiting mighty Jupiter, a truth that forever changed humanity’s understanding of our place in the cosmos. Earth was not the center of the Universe. For the first time in history, we look upon these moons as they orbit Jupiter and share in Galileo’s revelation. This is the motion of nature’s harmony.

NASA’s Juno spacecraft is scheduled to arrive at the giant planet Jupiter in July 2016 following a five-year trek. As the spacecraft nears the planet it executes a series of maneuvers to prepare for Jupiter orbit insertion. First, the spacecraft opens its main engine cover. Then Juno uses thrusters to re-orient itself so that its main engine points in the direction the spacecraft is moving. Juno’s thrusters then fire to increase the spacecraft’s rate of spin from 2 rotations per minute to 5 rotations per minute; the faster rate of rotation makes Juno more stable during the engine burn to come.

Juno fires its main engine for about 30 minutes to slow down and allow Jupiter’s gravity to capture the speeding spacecraft into orbit. Following the engine burn, Juno decreases its rate of spin and points its giant solar arrays back toward the sun and Earth (which at Jupiter’s location appear close together in the sky). At this point the spacecraft will be successfully in orbit around the giant world.

Secrets lie deep within Jupiter, shrouded in the solar system’s strongest magnetic field and most lethal radiation belts. On July 4, 2016, NASA’s Juno spacecraft will plunge into uncharted territory, entering orbit around the gas giant and passing closer than any spacecraft before. Juno will see Jupiter for what it really is, but first it must pass the trial of orbit insertion.